The Baltimore man whose death in police custody sparked riots and nationwide protests suffered the fatal injury when his head slammed into a bolt in the back of a police van after his arrest, a report said Thursday.

Freddie GrayFootage of Freddie Gray in police custody.

The probe into Freddie Gray’s death — which occurred while he was still in custody seven days later — found no evidence that his devastating spinal cord injuries were caused during his April 12 arrest, which was captured on camera, ABC News affiliate WJLA reported, citing multiple sources.

The sources had been briefed on the findings of a police investigation that was handed over to prosecutors Thursday as well as preliminary reports from the medical examiner’s office.

They said the ME found that Gray, 25, broke his neck and that a wound to his head matched a bolt in the rear of the van, the Washington, DC, station reported.

What exactly caused Gray to slam into the back of the van was unclear. The officer who was driving has not yet given a statement to authorities.

It was also unclear whether Gray himself caused the injury — as another prisoner in the van had reportedly told investigators.

That prisoner said he thought Gray “was intentionally trying to injure himself,” the Washington Post had reported.

He told investigators that Gray “was still moving around, that he was kicking and making noises” until the van arrived at the police station. He did not see Gray, because the van had a partition.

Baltimore Police Commissioner Anthony Batts said the other suspect also said the van’s driver did not speed, make sudden stops or drive erratically.

A camera outside a small grocery recorded the stop. Its owner, Jung Hyun Hwang, said two officers visited his store during the week of April 20 and later made a copy of the surveillance video.

Hwang said he did not review the video with police and didn’t know what was on it. His original recording, he said, was on a laptop that was stolen during the riots and looting Monday night.

Police had previously said the van stopped only three times, including to put leg cuffs on Gray and to pick up another prisoner.

The State’s Attorney’s Office will review the police findings and the results of its own investigation, then decide whether to seek criminal charges against any of the six cops involved.

All six were suspended following Gray’s April 19 death.

Billy Murphy, lawyer for Gray’s family, said his clients wanted a thorough investigation.

Protesters rally in front of the State’s Attorney’s Office in Baltimore.AP

“Let’s be patient. The family wants patience. The family is not interested in a rush to justice . . . Patience, people,” he said, according to the Baltimore Sun.

Gray, who had a history of non-violent arrests for drugs and other charges, was busted April 12 after he ran from cops while on probation. He was found to be carrying a switchblade.

Batts on Thursday provided no details of what was in the report and did not take questions at a news conference announcing its completion a day earlier than the Friday deadline he had set.

“I understand the frustration. I understand the sense of urgency . . . That is why we have finished it a day ahead of time,” said Batts, adding that more than 30 detectives were assigned to the case.

Batts said cops would continue investigating at the direction of State’s Attorney Marilyn Mosby.

“Getting to the right answer is more important than speed,” the commissioner said.

Mosby stressed that her office was conducting its own probe.

“We are not relying solely on their findings but rather the facts that we have gathered and verified. We ask for the public to remain patient and peaceful and to trust the process of the justice system,” she said.

Baltimore Mayor Stephanie Rawlings-Blake vowed on Thursday that the city would get justice for Gray, who was black.

“If, with the nation watching, three black women at three different levels can’t get justice and healing for this community, you tell me where we’re going to get it in our country,” she said, referring to herself, Mosby and new US Attorney General Loretta Lynch.

Meanwhile, a 10 p.m.-to-5 a.m. curfew will remain in effect through the weekend, Batts said.

On Thursday evening, dozens of protesters marched through Baltimore’s downtown area, though no violence was reported. Police and National Guard presence remained heavy.

Police also said more than half of the 201 people detained in Monday’s riots had been released because charges couldn’t be filed within the 48-hour time limit.

Cops were reviewing video and hope to bring charges against many of those who were released.

They also said that 98 officers were injured in the violence, and that 43 required hospital treatment. Thirteen are out on medical leave while 15 are assigned to light duty, they said.